Control apparatus that performs focusing by imaging-plane phase difference AF, image capturing apparatus, control method, and non-transitory computer-readable storage medium

Abstract

A control apparatus includes an acquirer ( 204 a ) which acquires a first signal and a second signal that correspond to light beams passing through different pupil regions of an image capturing optical system, a calculator ( 204 b ) which performs a plurality of filtering processes with different bands for the first signal and the second signal to calculate a plurality of defocus amounts and reliabilities based on the first signals and the second signals where the respective filtering processes have been performed, and a determiner ( 209 ) which determines a defocus amount used for focusing from among the plurality of defocus amounts based on a difference between the plurality of defocus amounts and at least one of the plurality of reliabilities.

What is claimed is: 
     
       1. A control apparatus comprising:
 at least one processor; and 
 a memory including instructions that, when executed by the at least one processor, cause the at least one processor to operate as:
 an acquirer configured to acquire a first signal and a second signal that correspond to light beams passing through different pupil regions of an image capturing optical system, 
 a calculator configured to perform a plurality of filtering processes with different bands for the first signal and the second signal to calculate a plurality of defocus amounts and reliabilities based on the first signals and the second signals where the respective filtering processes have been performed, and 
 a determiner configured to determine a defocus amount used for focusing from among the plurality of defocus amounts based on a difference between the plurality of defocus amounts and at least one of the plurality of reliabilities, 
 
 wherein the plurality of filtering processes include:
 a first filtering process for extracting the first and second signals with a first frequency band, and 
 a second filtering process for extracting the first and second signals with a second frequency band higher than the first frequency band, 
 
 wherein the calculator is configured to calculate, as the plurality of defocus amounts and reliabilities:
 a first defocus amount and a first reliability based on the first and second signals where the first filtering process has been performed, and 
 a second defocus amount and a second reliability based on the first and second signals where the second filtering process has been performed, and 
 
 wherein when the difference between the first defocus amount and the second defocus amount is greater than a first threshold value, the calculator is configured to determine the first defocus amount as the defocus amount used for the focusing. 
 
     
     
       2. The control apparatus according to  claim 1 , wherein the calculator is configured to:
 determine the second defocus amount as the defocus amount used for the focusing when the second reliability is higher than the first reliability and the second reliability is higher than a predetermined reliability threshold value, and 
 determine the first defocus amount as the defocus amount used for the focusing when the second reliability is lower than the first reliability or the second reliability is lower than the predetermined reliability threshold value. 
 
     
     
       3. The control apparatus according to  claim 1 , wherein:
 the plurality of filtering processes include a third filtering process for extracting the first and second signals with a third frequency band higher than the second frequency band, and 
 the calculator is configured to calculate a third defocus amount and a third reliability based on the first and second signals where the third filtering process has been performed. 
 
     
     
       4. The control apparatus according to  claim 3 , wherein when the difference between the second defocus amount and the third defocus amount is greater than a second threshold value, the calculator is configured to determine the second defocus amount as the defocus amount used for the focusing. 
     
     
       5. The control apparatus according to  claim 4 , wherein the calculator is configured to:
 determine the third defocus amount as the defocus amount used for the focusing when the third reliability is higher than the second reliability and each of the second reliability and the third reliability is higher than a predetermined reliability threshold value, and 
 determine the second defocus amount as the defocus amount used for the focusing when the third reliability is lower than the second reliability or the at least one of the second reliability and the third reliability is lower than the predetermined reliability threshold value. 
 
     
     
       6. The control apparatus according to  claim 4 , wherein the second threshold value is smaller than the first threshold value. 
     
     
       7. The control apparatus according to  claim 4 , wherein each of the first threshold value and the second threshold value is greater than a depth of focus. 
     
     
       8. A control apparatus comprising:
 at least one processor; and 
 a memory including instructions that, when executed by the at least one processor, cause the at least one processor to operate as:
 an acquirer configured to acquire a first signal and a second signal that correspond to light beams passing through different pupil regions of an image capturing optical system, 
 a calculator configured to calculate a defocus amount and a reliability based on the first signal and the second signal, and 
 a focus controller configured to control a focus lens depending on the defocus amount and the reliability, 
 
 wherein the focus controller is configured to change control that depends on the defocus amount and the reliability between in a first mode where focus control is performed over a whole of a movable range of the focus lens and in a second mode where the focus control is performed within a predetermined range based on a focus lens position set by a user, and 
 wherein the focus controller changes a condition of a frame addition that depends on the defocus amount and the reliability between in the first mode and the second mode. 
 
     
     
       9. The control apparatus according to  claim 8 , wherein the focus controller is configured to change the number of times of driving the focus lens that depends on the defocus amount and the reliability between in the first mode and the second mode. 
     
     
       10. The control apparatus according to  claim 9 , wherein:
 the calculator is configured to perform a plurality of filtering processes with different bands for the first and second signals to calculate a plurality of defocus amounts based on the first and second signals where the respective filtering processes have been performed, and 
 the focus controller is configured to control the focus lens based on a defocus amount with a highest band of the plurality of defocus amounts calculated by the calculator in the second mode.